Smart Grid + Demand Response = Underrated Renewable Energy Storage?


Photo: Flickr, CC

Shaping Demand to Match Supply

Serious discussions about renewable energy usually end up being about energy storage too. Wind and solar power are both intermittent sources of electricity, so if we want to power a significant fraction of our power grids with them, we need a way to store power for windless and cloudy days. The most talked about candidates are batteries, molten salts, pumping water uphill, compressed air, etc. All of this has to do with supply, but what about demand? "Demand response" is very underrated and might play a big role in the future. Read on for details.


Photo of Jon Wellinghoff, public domain

Scientific American just published an interview with the chairman of the Federal Energy Regulatory Commission (FERC), Jon Wellinghoff. Part of the Q&A; is about demand response:

Scientific American A common refrain in this country is that as long as you keep increasing wind and solar, we are going to need storage, otherwise there are never going to be major factors in our energy portfolio. Does this smarter grid change that?

Jon Wellinghoff: Well, it helps, because we have to think what storage really is. There is more storage in the water heaters in this country than there is in all the pumped [water] storage in the entire United States. So all you have to do is be able to control those water heaters and you have storage just like that. So, there is storage in the buildings. Think about all of the wholesale refrigeration warehouses that are in this country. All you have to do is vary the temperature in there by a very small amount and you have huge amounts of potential storage that would not affect the stored commodities in those warehouses but yet allow that system to functionally act as storage. All we have to do is control it. We have to put in the controls and the communication equipment, and we have effectively huge amounts of storage that is available to us in this country, which we just have to go and get it. ... It is called demand response, and you can use it in ways that will ultimately make the grid work better and put more and more wind and solar and other renewables onto the grid at the same time.


How Demand Response Works
So the idea is to have a smart grid that can control certain things that require a lot of energy to shape demand. There are many things that, within certain parameters, can be played with to match electrical supply and demand. For example, let's say that the wind is blowing very strong at night but demand is low. You could lower the temperature in many big refrigerated warehouses with that extra electricity, and over the next day, the temp would progressively rise back up to normal levels, and the A/C system would require less electricity during that time, reducing demand during the following day. It's a way to "store" the extra juice from wind farms. On the flip side, if you have a cloudy windless day and your solar panels and wind farms are mostly idle, you could lower the temperature by a couple degrees on thousands and thousands of water heaters, and let the temps rise by a couple degrees in refrigerated warehouses (but within parameters that would make it safe for food and for water quality), thus reducing demand for electricity at that moment.

You might still have to import electricity from other regions or fire up backup power plants, but that'll happen a lot less often than if you didn't have a smart grid that could do "demand response".

Paying You to Save Electricity
Later in the interview, Mr. Wellinghoff mentions that it would be possible to opt out of such a program, but that he expects that most people would stick with it because it would pay (it's cheaper for a utility to pay many people a little to shape their electricity demand than to build new power plants or transmission lines).

Via Scientific American
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